Timecode off on BMMCC and Tascam DR-701D

I got two tentacle setup on my BMMCC and Tascam DR-701D. I’ve both tried feeding the BMMCC through line and refrence input. Timecode is being fed and the tentacles are synced with one slaved via the line cable, both flashes green. But when I bring the Tascam and BMMCC into Davinci Resolve to sync it its always off by at least a second.

Any ideas why this can be? Have tried both 44.1khz and 48khz on the Tascam.

How can I determine if its the camera or recorder that is recording the wrong timecode?